Dial tuning device



Filed Oct. 4, 1937 ken line 2-2 of Fig. 1 showing the connection A usual hand tuning knob 29 is likewise joursired station; dio set in a well known manner.

Fig. 3 is a similar view showing the operators The front of the radio set includes an annular hand completing the tuning operation by means escutcheon 33 which overlies the outer edge of 35 of fine adjustin knob; the greater portion of the casting 20 so as to Fig. 4 is a front elevation of the same; and D I Y finish t Same. Fig. 5 is a view similar to Fig. 3 showing a The center of the dial 20 is open to receive a UNITED STATES PATENT OFFICE DIAL TUNING DEVICE Edwin G. Bradshaw, Chicago, Ill., assignor to Wells-Gardner & Company, Chicago, 111., a corporation of Illinois Application October 4, 1937, Serial No. 167,222

5 Claims. (01. 74-10) An object of this invention is to provide an to rotate therewith. This spider has spaced arms improved and simplified form of tuning device w and has on its periphery a dial of Bakelite of the general type now referred to as teleor the like 20 having a series of depressions 2| phone dial tuners. Such a tuner has a relaall preferably at an equal distance from the tively large tuning dial which is operatively concenter. One of these has been omitted to pera nected to a tuning condenser of a radio receivmit insertion of a zero mark showing the ends ing set so that as the dial is turned it will roof the swing of the disc, and a stop 20 is suptate a gang condenser which controls a plurality plied at this point. It will be noted that the of stages of tuned radio frequency. bottom of each one of the depressions 2| carries A telephone dial of this character has a series a disc 22 and is held in place and protected by of depressions each one of which more or less means of a disc 23 of a clear transparent materoughly corresponds to asetting of the condenser al u as C u d Which also P o es a for a given radio broadcasting station when said smooth bearing for the operators finger. If depression is brought to a predetermined posithese become scratched or worn, they can readtion of the dial, usually its lowermost position. ily be replaced. Each disc 22 may be marked It isan object of the present invention to sim- With the call letters of a desired radio broadplify a dial tuner of this type and at the same casting station whose position is nearest that of time to render the tuning of a given station that particular depression when the latter is at rapid and accurate. 1 I the bottom of its swing as shown in Figs. 1 and 2.

These and other objects, as will hereinafter A knob 24 is mounted on a shaft 25, the latter appear, are accomplished by this invention, being rotatably and slidably mounted in suitwhich is fully described in the following speciable bearings as H and H in the frame ll. fication and shown in the accompanying draw- The shaft 25 is provided with a collar 26 sein in hich; cured thereto and pressed normally against the Fig. 1 is a partial front elevation of a radio bearing H by m n of a compression pri 25 receiving set showing one form of a dial tuner 21. The knob 24 is provided with a rubber washembodying the present invention; er 28 or the like which is adapted to bear against Fig. 2 is a partial vertical section on the brothe outer circular edge of the casting 20.

between the dial tuner and the gang condenser naled in the frame II and has a sheave 30 act- 30 which it controls with an operators finger in ing through a flexible Wire drive 3| with a sheave place in the first step of roughly tuning a de- 32 on the sleeve [6 for manually tuning the ramodified form of the device in which the fine d 34 Which is p q and ua ed On its adjustment is performed by the operators inouter portion while the inner portion 35 is transdex finger while in the depression in the tunp e This d is retained y a p ring ing dial, Back of the transparent center lies an opaque The embodiment illustrated in Figs. 1 to 4 plate 31 which is supported on the stud l8. It is comprises a radio receiving set having a chassis opaque except for the transparent arrow 38 frame I0 above which is mounted in any desired which serves as a marker for the graduated scale manner, not herein shown, a metal frame H on the disc 34. A translucent sheet of paper or in which is suitably journaled a shaft I2 of a the like 39 is placed inside the arms of the spider gang condenser l3. A gear M on the shaft [2 to diffuse the light and thus prevent shadows meshes with a pinion l5 (preferably having being cast thereby when the dial is illuminated slightly more than one-half of the number of by lamps 40. teeth of the gear M) on a, sleeve I6 which is The operation of this device is as follows: with rotatably mounted on a stud l7 secured at [8 the tuning dial having depressions some of which to the frame H. are marked with the call letters of the station The sleeve I6 carries at its forward end a to which they correspond, the operator selects spider H! which is firmly secured thereon so as one such station which he desires to tune. He

then inserts his finger in that particular depression and turns the disc until that depression as 2P is at the lowermost position as shown in Figs. 1 and 2. This he can determine even in the dark by the fact that his finger in this position is resting on the top of the knob 24. It may happen that in this position the dial will be sharply tuned; If so, he can withdraw his finger and permit the set to stand in that position. If, however, he desires to tune the set more sharply, he will withdraw his finger, as shown in. Fig. 3 and use his hand which is already set to grasp the knob 25 to press the latter in until the rubber Washer 28 engages the circular periphery of the casting 20 at which time he can slowly turnthe knob 24 until the set is sharply tuned in for that desired station. Owing to the fact that the knob 24 is much smaller than the diameter of the casting 20, this tuning can be very delicately done. Thus with a little practice the operator gets to know that for a given station he can swiftly turn the dial down to the lowermost position with his index finger, and as he does so, grasp the knob 24 with his thumb and second finger and quickly tune the set sharply for that station.

In Fig. 5 is shown a modified form of the device in which a tuning knob 2 is mounted on a shaft 25 which is rotatable but which does not drive a dial [9 except through the agency of the operator-s finger. Thus having brought the set quickly to a roughly tuned position, .the operator by keeping his finger in the depression 21* as shown in Fig. 5 can do the fine tuning while he slowly rotates his hand about the shaft 25 This latter form of fine tuning can also be employed withthe set of Figs. 1 the if desired. In that case the operator would not press the knob 24 in, as shown in Fig. 3, but would merely rotate his hand while the index finger is in the position shown in the depression 2 I of Fig. 2.

Thus it will be seen that a very simple yet efiicient form of telephone type tuning dial is provided.

I claim:

1; In a radio receiving set, a tuning condenser, a tuning dial operatively connected thereto, said dial having a series of depressions adapted to receive the finger of an operator, and a knob mounted adjacent the dial so that when the operators finger is in a depression, it can rest on the knob to assist in tuning.

2. In a radio receiving set, a tuning condenser, a tuning dial operatively connected thereto, said dial having a series of depressions adapted to receive the finger of an operator, and a knob rotatably mounted adjacent the dial so that when the operators finger is in a depression, it can rest on the knob to assist in tuning.

3. In a radio receiving set, a tuning condenser, a tuning dial operatively connected thereto, said dial having a series of depressions adapted to receive the finger of an operator, and a knob rotatably mounted adjacent the dial so that when the'operators finger is in a depression, it can rest on the knob to assist in tuning, the knob being operatively connected to the dial so that rotation of the knob rotates the dial.

4. In a radio receiving set, a tuning condenser, a tuning dial operatively connected thereto, said dial having a series of depressions adapted to receive the finger of an operator, and a knob rotatably mounted adjacent the dial so that when the operators finger is in a depression, it can rest on the knob to assist in tuning, the knob being movable so as to be operatively connected to the dial so that'rotation of the knob rotates the dial. Y

5. In a radio receiving set, a tuning condenser, a tuning dial operatively connected thereto, said dial having a series of depressions adapted to receive the finger of an operator, and a knob rotatably mounted adjacent the dial so that when the operators finger is in a depression, it can rest on the knob to assist in tuning, the knob being movable endwise'so as tov be'operatively connected to the dial so that'rotation of the knob rotates the dial.

EDWIN G. BRADSHAW. 

